Translation and validation of the 8-item Contact Lens Dry Eye Questionnaire (CLDEQ-8) among Japanese soft contact lens wearers: The J-CLDEQ-8

Purpose: To translate and validate a Japanese version of the 8-item Contact Lens Dry Eye Questionnaire (CLDEQ-8) among a multicenter sample of Japanese-speaking soft contact lens (SCL) wearers in Japan. Methods: The study comprised two phases, 1) forward and backward translation of the CLDEQ-8 into Japanese, 2) cross-sectional validation of Japanese CLDEQ-8 (J-CLDEQ-8) among Japanese spherical disposable SCL wearers (daily disposable, 2 week, or monthly disposable) against their Overall Opinion of SCLs, and 3) repeatability testing in a subset of subjects. Results: 300 subjects (118 males and 182 females) completed the J-CLDEQ-8 and anchoring Gestalt SCL questions. The J-CLDEQ-8 had a strong significant linear relationship to Overall Opinion of SCLs and the Self-Assessment of Eye Dryness. The Gestalt Eye Sensitivity question did not translate well in Japanese and the relationship between it and the J-CLDEQ-8 was not linear. A cutoff score of < 11 points with the J-CLDEQ-8 related best to patients who reported "Excellent" or "Very Good" Overall Opinion of their SCLs, differing slightly from the North American CLDEQ-8 cutoff of < 12 points. This < 11 points cutoff yielded accuracy of 0.66, and a sensitivity of 0.67 and specificity of 0.66, very similar to the values for the original CLDEQ-8. Conclusions: The J-CLDEQ-8 was capable of differentiating SCL wearers with different Overall Opinions of their SCLs, comparable to the original CLDEQ-8 in English.